Conventionally, an electric power steering apparatus has been known as a steering apparatus of such a type. The electric power steering apparatus is designed to provide steering assist torque while controlling the amount of electricity supplied to an electric motor in accordance with a steering state of a steering wheel. However, such an electric power steering apparatus consumes a considerable amount of electrical power. Therefore, when the performance of a battery, which is a power source mounted on a vehicle, drops, supply of electric power to the electric motor becomes insufficient or power supply voltage temporarily drops when the electric motor operates, whereby the electric power steering apparatus fails to provide a designed performance. In order to overcome such a problem, in an electric power steering apparatus disclosed in Japanese Patent Application Laid-Open (kokai) No. S63-64869, upon detection of a situation in which a large amount of electric power must be supplied to an electric motor, supply of electricity to other electric devices (electrical loads mounted on a vehicle (hereinafter referred to as “vehicle electrical loads”)) is temporarily stopped, whereby imposition of an excessively large load on a battery is prevented. Specifically, when the rotational speed of an engine becomes equal to or less than a predetermined level and a change rate of the steering angle of a steering wheel becomes equal to or greater than a predetermined level, supply of electricity to other electric devices is stopped.